Preventing all the complications of hyperglycaemia: not a straightforward task

Epidemiological studies have found positive relationships between measures of glycaemia and adverse fetal and maternal pregnancy outcomes,1 macrovascular disease2,3 and the microvascular complications of diabetes.2,3 The relationship between glycaemia and microvascular disease is more complicated, as there is an inflection point below which the risk is very low, but beyond which it rises sharply. The inflection point of the relationship between glycaemia values and the prevalence of retinopathy has been used to determine both the glucose tolerance test values and the glycated haemoglobin (HbA1c) level used to diagnose diabetes (see Figure 1 in reference 3).

Epidemiological studies have also found that the prevalence of hyperglycaemia associated with pregnancy,4,5 macrovascular disease6 and microvascular complications7,8 is modified — usually increased — by other known risk…